package lanqiao;
import java.util.*;
public class Main {
public static Stack InitStack() {
Stack stack=new Stack(0);//构建一个节点stack当作头节点data表示stack长度
return stack;
}
public static Stack Push(Stack stack,int num) {//头插法
if(stack.next!=null) {
Stack s=new Stack(num);
s.next=stack.next;
stack.next=s;
stack.data++;
}else {
Stack s=new Stack(num);
stack.next=s;
stack.data++;
}
return stack;
}
public static Stack Pop(Stack stack) {//头删法(自己起的哈哈哈哈)
if(stack.data<1) {
System.out.println("该栈以空!!!");
}else {
stack.next=stack.next.next;
stack.data--;
}
return stack;
}
public static int GetTop(Stack stack) {
if(stack.data==0) {
System.out.println("该栈为空栈!");
return -1;
}
return stack.next.data;
}
public static void main(String[] args) {
Stack stack=InitStack();
Push(stack,5);
Push(stack,2);
Push(stack,1);
System.out.println("栈顶元素为:"+GetTop(stack));
Pop(stack);
System.out.println("栈顶元素为:"+GetTop(stack));
Push(stack,999);
System.out.println("栈顶元素为:"+GetTop(stack));
}
}
class Stack{
int data;
Stack next;
public Stack() {
}
public Stack(int data) {
this.data=data;
}
}
结果:
栈顶元素为:1
栈顶元素为:2
栈顶元素为:999